Personal alarm,  quite old so won't have the 10 year warranty but it does work as we tried it recently.   It is loud.  You just pull the pin out on the right hand side d

This Is quite an old personal alarm but it does work as we tried it recently.  You simply pull the pin out on the right hand side and reinsert it to switch off.  It is very loud.  Measurements 7 cm x 6 cm x 2.5 cm.